有機發光二極體（organic light-emitting diode, OLED）為極具潛力的照明產品，目前量產多採用真空蒸鍍製程，在量產上受限於面積與製程成本等問題，因此學界與業界致力研究溼式塗佈之OLED製程，使其元件表現及價格符合市場需求。
　　本研究主要目的為探討影響溼式製程OLED元件表現之因素，其指標包含效率與壽命。本研究以先前本實驗室建立的綠光OLED材料與元件結構為基礎，製作發光面積為0.25 cm2之三有機層綠光OLED元件，以旋轉塗佈法製備三有機層，由效率與壽命判斷較適化製程條件，同時確認影響元件表現的顯著因子，在亮度3000 cd/m2下功率效率達到6 lm/W，操作電壓約8 V，以此作為起始亮度所測得之壽命由低於0.5 hr上升至超過20 hr。元件衰退之關鍵機制為材料的成膜狀態，因此以不同方式觀測膜面與膜層內部的形態，初步建立有機薄膜的分析方法。本研究另行測試四有機層OLED元件之表現，以真空蒸鍍法製備電子傳輸層，確認其獨立堆疊於發光層上對於元件效率與壽命的影響顯著性，亮度3000 cd/m2下功率效率達11 V以上，操作電壓則低於7 V；起始亮度1000 cd/m2所測得之壽命超過260 hr。

Organic light-emitting diodes (OLEDs) have great potential on lighting application. OLED panels has been commercialized with high cost partly due to the vacuum deposition process. In order to reduce the process cost, solution process is expected to be applied on OLED fabrication. Therefore, researches on solution-processed OLEDs have received extensive attention to meet the market demands.
The main purpose of this research is to analyze the factors that would influence the performance, including efficiency and lifetime, of OLED lighting devices. The green phosphorent OLED devices with 0.25 cm2 emissive area were fabricated and the organic layers except electron transport layer were produced by spin coating as test samples.
In the OLED devices with three organic layers, the power efficiency at the luminance of 3000 cd/m2 reached 6 lm/W with operating voltage at about 8 V. The lifetime with the initial luminance of 3000 cd/m2 is increased from less than 0.5 hr to more than 20 hr. The morphology of the organic thin films was considered to be the key factor to influence the device performance, so the analysis on the film surface and the whole layer was carried out. In the devices with four organic layers, the power efficiency at the luminance of 3000 cd/m2 reached 11 lm/W with operating voltage less than 7 V. The lifetime with the initial luminance of 1000 cd/m2 is increased to more than 260 hr.

1. 葉修鋒, 以狹縫式塗佈技術製備大面積小分子有機發光二極體, in 化學工程學系. 2013, 國立清華大學.
2. 羅少軒, 以溼式塗佈技術進行OLED發光元件大型化之分析, in 化學工程學系. 2015, 國立清華大學.
3. 鍾長廷, 多光色溶液製程有機發光二極體之研製, in 化學工程學系. 2015, 國立清華大學.
4. 張簡俊寧, 有機發光二極體液態塗佈互溶改善之研究, in 化學工程學系. 2015, 國立清華大學.
5. Pope, M., H.P. Kallmann, and P. Magnante, Electroluminescence in organic crystals. Journal of Chemical Physics, 1963. 38: p. 2042-2043.
6. Tang, C.W. and S.A. VanSlyke, Organic electroluminescent diodes. Applied Physics Letters, 1987. 51: p. 913-915.
7. Tang, C.W., S.A. VanSlyke, and C.H. Chen, Electroluminescence of doped organic thin films. Journal of Applied Physics, 1989. 65: p. 3610-3616.
8. 陳金鑫 and 黃孝文, 夢幻顯示器：OLED材料與元件. 2007: 五南圖書出版有限公司.
9. Burroughes, J.H., et al., Light-emitting diodes based on conjugated polymers. Nature, 1990. 347: p. 539-541.
10. Baldo, M.A., et al., Highly efficient phosphorescent emission from organic electroluminescent devices. Nature, 1998. 395: p. 151-154.
11. Baldo, M.A., et al., Very high-efficiency green organic light-emitting devices based on electrophosphorescence. Applied Physics Letters, 1999. 75: p. 4-6.
12. Adachi, C., et al., Nearly 100% internal phosphorescence efficiency in an organic light emitting device. Journal of Applied Physics, 2001. 90: p. 5048-5051.
13. Kondakov, D.Y., et al., Nonradiative recombination centers and electrical aging of organic light-emitting diodes: Direct connection between accumulation of trapped charge and luminance loss. Journal of Applied Physics, 2003. 93: p. 1108-1119.
14. 何孟寰, 黃孝文, and 陳金鑫, 有機電激磷光材料與OLED磷光元件之發展近況. 化學, 2005. 63: p. 443-462.
15. Kawamura, Y., S. Yanagida, and S.R. Forrest, Energy transfer in polymer electrophosphorescent light emitting devices with single and multiple doped luminescent layers. Journal of Applied Physics, 2002. 92: p. 87-93.
16. Chao, Y.-C., et al., Highly efficient solution-processed red organic light-emitting diodes with long-side-chained triplet emitter. Synthetic Metals, 2011. 161: p. 148-152.
17. Kido, J., et al., White light-emitting organic electroluminescent devices using the poly(N-vinylcarbazole) emitter layer doped with three fluorescent dyes. Applied Physics Letters, 1994. 64: p. 815-817.
18. Kristukat, C., et al., Lifetime determination procedure for OLED lighting panels and proposal for standardisation, in Organic light-emitting diodes (OLEDs), A. Buckley, Editor. 2013, Woodhead Publishing Limited. p. 601-634.
19. Buckley, A.R., C.J. Yates, and I. Underwood, Towards a generic OLED lifetime model. Journal of the Society for Information Display, 2009. 17: p. 611-616.
20. Popovic, Z.D. and H. Aziz, Reliability and degradation of small molecule-based organic light-emitting devices (OLEDs). IEEE Journal of Selected Topics in Quantum Electronics, 2002. 8: p. 362-371.
21. Féry, C., et al., Physical mechanism responsible for the stretched exponential decay behavior of aging organic light-emitting diodes. Applied Physics Letters, 2005. 87: p. 213502.
22. Zhang, J.P., et al., Experimental test and life estimation of the OLED at normal working stress based on the luminance degradation model. Luminescence, 2014. 30: p. 371-375.
23. Stolka, M., Organic light emitting diodes (OLEDs) for general illumination update 2002. 2002: Optoelectronics Industry Development Association.
24. 陳光榮, 軟性OLED阻水氧層技術, in 材料世界網電子報. 2010, 材料世界網.
25. McElvain, J., et al., Formation and growth of black spots in organic light-emitting diodes. Journal of Applied Physics, 1996. 80: p. 6002-6007.
26. Hayer, A., et al., Concepts for solution-processable OLED materials at Merck. Journal of Information Display, 2011. 12: p. 57-59.
27. Oikawa, K., Development of OLED lighting applications using phosphorescent emission system, in PE 2012 Exhibition & Conference. 2012.
28. Höfle, S., et al., Suppressing molecular aggregation in solution processed small molecule organic light emitting diodes. Organic Electronics, 2014. 15: p. 337-341.
29. Han, E.-M., et al., Crystallization of organic thin films for electroluminescent devices. Thin Solid Films, 1996. 273: p. 202-208.
30. Xia, S.C., et al., Oled device operational lifetime: insights and challenges, in 2007 International Reliability Physics Symposium. 2007. p. 253-257.
31. Kondakov, D.Y., W.F. Nichols, and W.C. Lenhart, Structural identification of chemical products and mechanism of operational degradation of OLEDs, in International Symposium of the Society-for-Information-Display (SID 2007). 2007, SID INTERNATIONAL SYMPOSIUM DIGEST OF TECHNICAL PAPERS. p. 1494-1496.
32. Adachi, C., K. Nagai, and N. Tamoto, Molecular design of hole transport materials for obtaining high durability in organic electroluminescent diodes. Applied Physics Letters, 1995. 66: p. 2679-2681.
33. Trlifaj, M., Nonradiative destruction of triplet excitons by excess electrons in organic crystals. Journal of Physics, 1973. 23: p. 558-566.
34. Shen, J., et al., Degradation mechanisms in organic light emitting diodes. Synthetic Metals, 2000. 111-112: p. 233-236.
35. Lee, S.T., Z.Q. Gao, and L.S. Hung, Metal diffusion from electrodes in organic light-emitting diodes. Applied Physics Letters, 1999. 75: p. 1404-1406.
36. 李孟庭, OLED壽命提升課題探討. 工業材料雜誌, 2008. 256: p. 124-133.
37. Popovic, Z.D., et al., Life extension of organic LED's by doping of a hole transport layer. Thin Solid Films, 2000. 363: p. 6-8.
38. Culligan, S.W., et al., Effect of hole mobility through emissive layer on temporal stability of blue organic light-emitting diodes. Advanced Functional Materials, 2006. 16: p. 1481-1487.
39. Meerheim, R., et al., Influence of charge balance and exciton distribution on efficiency and lifetime of phosphorescent organic light-emitting devices. Journal of Applied Physics, 2008. 104: p. 014510.
40. Yoo, J.-D., et al., Soluble processed low-voltage and high efficiency blue phosphorescent organic light-emitting devices using small molecule host systems. Organic Electronics, 2012. 13: p. 586-592.
41. Yoo, S.-J., et al., A new electron transporting material for effective hole-blocking and improved charge balance in highly efficient phosphorescent organic light emitting diodes. Journal of Materials Chemistry C, 2013. 1: p. 2217-2223.
42. Duan, L., et al., Solution processable small molecules for organic light-emitting diodes. Journal of Materials Chemistry, 2010. 20: p. 6392-6407.
43. Xie, H.-Z., et al., Reduction of self-quenching effect in organic electrophosphorescence emitting devices via the use of sterically hindered spacers in phosphorescence molecules. Advanced Materials, 2001. 13: p. 1245-1248.
44. Choi, S.H., et al., Improved efficiency and lifetime of organic light-emitting diode with lithium-quinolate-doped electron transport layer. The Japan Society of Applied Physics, 2009. 48: p. 062101.
45. Shaheen, S.E., et al., Bright blue organic light-emitting diode with improved color purity using a LiF/Al cathode. Journal of Applied Physics, 1998. 84: p. 2324-2327.
46. Wang, X.J., et al., Enhancement of electron injection in organic light-emitting devices using an Ag/LiF cathode. Journal of Applied Physics, 2004. 95: p. 3828-3830.
47. Ganzorig, C. and M. Fujihira, A lithium carboxylate ultrathin film on an aluminum cathode for enhanced electron injection in organic electroluminescent devices. Japanese Journal of Applied Physics, 1999. 38: p. 1348-1350.
48. Matsumura, M., K. Furukawa, and Y. Jinde, Effect of Al/LiF cathodes on emission efficiency of organic EL devices. Thin Solid Films, 1998. 331: p. 96-100.
49. Su, S., et al., Dependence study of optoelectronics performance on carefully differed LiF thickness in Alq3 based OLEDs. Optics and Photonics Journal, 2013. 3: p. 256-259.
50. Kido, J. and T. Matsumoto, Bright organic electroluminescent devices having a metal-doped electron-injecting layer. Applied Physics Letters, 1998. 73: p. 2866-2868.
51. Kurczewska, H. and H. Bässler, Energy transfer across an anthracene-gold interface. Journal of Luminescence, 1977. 15: p. 261-266.
52. Ummartyotin, S., et al., Deposition of PEDOT:PSS nanoparticles as a conductive microlayer anode in OLEDs device by desktop inkjet printer. Journal of Nanomaterials, 2011. 2011: p. 7.
53. Zhou, Y., et al., Mild oxygen plasma treated PEDOT:PSS as anode buffer layer for vacuum deposited organic light-emitting diodes. Chemical Physics Letters, 2006. 427: p. 394-398.
54. Benor, A., et al., Efficiency improvement of fluorescent OLEDs by tuning the working function of PEDOT:PSS using UV-ozone exposure. Organic Electronics, 2010. 11: p. 938-945.
55. Lide, D.R., CRC Handbook of Chemistry and Physics. 2003-2004.
56. Schlatmann, A.R., et al., Indium contamination from the indium–tin–oxide electrode in polymer light-emitting diodes. Applied Physics Letters, 1996. 69(12): p. 1764-1766.
57. Jeon, S.K. and J.Y. Lee, Four times lifetime improvement of blue phosphorescent organic light-emitting diodes by managing recombination zone. Organic Electronics, 2015. 27: p. 202-206.
58. Meyerhofer, D., Characteristics of resist film produced by spinning. Journal of Applied Physics, 1978. 49: p. 3993-3997.
59. Tyona, M.D., A theoritical study on spin coating technique. Advances in Materials Research, 2013. 2: p. 195-208.
60. Zabihi, F., et al., Morphology, conductivity, and wetting characteristics of PEDOT:PSS thin films deposited by spin and spray coating. Applied Surface Science, 2015. 338: p. 163-177.
61. Mao, C., et al., Considerable improvement in the stability of solution processed small molecule OLED by annealing. Applied Surface Science, 2011. 257: p. 7394-7398.
62. Baldo, M.A., C. Adachi, and S.R. Forrest, Transient analysis of organic electrophosphorescence. II. Transient analysis of triplet-triplet annihilation. Physical Review B, 2000. 62: p. 10967-10977.
63. Reineke, S., K. Walzer, and K. Leo, Triplet-exciton quenching in organic phosphorescent light-emitting diodes with Ir-based emitters. Physical Review B, 2007. 75: p. 125328.
64. Murawski, C., K. Leo, and M.C. Gather, Efficiency roll-off in organic light-emitting diodes. Advanced Materials, 2013. 25: p. 6801-6827.
65. Aziz, H. and Z.D. Popovic, Degradation phenomena in small-molecule organic light-emitting devices. Chemical Materials, 2004. 16: p. 4522-4532.
66. Fenter, P., et al., Thermally induced failure mechanisms of organic light emitting device structures probed by X-ray specular reflectivity. Chemical Physics Letters, 1997. 277: p. 521-526.
67. Kwong, R.C., et al., High operational stability of electrophosphorescent devices. Applied Physics Letters, 2002. 81: p. 162-164.
68. Rezvani, M.H., et al., Effect of solvents, their mixture and thermal annealing on the performance of solution processed polymer light-emitting diodes. Materials, 2013. 6: p. 1994-2006.
69. Phatak, R., Dependence of dark spot growth on cathode/organic interfacial adhesion in Organic Light Emitting Devices, in Electrical and Computer Engineering. 2011, University of Waterloo: Waterloo, Ontario, Canada.
70. Lang, U., et al., Microscopical investigations of PEDOT:PSS thin films. Advanced Functional Materials, 2009. 19: p. 1215-1220.
71. Xu, J., et al., Crosslinked remote-doped hole-extracting contacts enhance stability under accelerated lifetime testing in perovskite solar cells. Advanced Materials, 2016. 28: p. 2807-2815.
72. Kim, Y., et al., Accelerated pre-oxidation method for healing progressive electrical short in organic light-emitting devices. Applied Physics Letters, 2003. 82: p. 2200-2202.
73. 孫亞賢, 劉峻佑, and 簡士偉, 低掠角小角度X光散射原理及在高分子薄膜結構之應用. 科儀新知, 2013. 34: p. 61-70.